PAC International RSIC-SI-1 ULTRA
RSIC-SI-1 ULTRA is a heavy-duty resilient isolation clip engineered to decouple walls and ceilings, cutting structure-borne vibration and boosting STC/IIC performance. Its factory-tuned steel spring, elastomer damping, and hat-channel mount deliver repeatable results across multifamily, studio, office, and healthcare projects where noise control, privacy, and comfort are priorities.
- High Isolation Performance: Robust spring-and-rubber design breaks the vibration path, reducing structure-borne transmission and improving real-world STC/IIC in ceiling systems.
- Heavy-Duty Capacity: Engineered for higher loads with multi-layer gypsum — supports dense acoustic assemblies without sagging.
- Versatile Applications: Ideal for multifamily, studios, offices, schools, and healthcare — anywhere noise control, privacy, and comfort matter.
- Consistent, Repeatable Results: Factory-tuned isolation element reduces installer variability compared with ad-hoc decoupling methods.
- Durable Construction: Corrosion-resistant hardware and resilient elastomer maintain isolation under long-term compression, temperature swings, and building movement.
Online orders up to 4,999 pieces. For anything larger, call (415) 864-4440 and we'll price the project with you.
Volume pricing
$44.95 per clip. Order 250+ clips and pay $44.55 per clip — an extra $0.40 off per clip for each additional 250 clips, down to a $42.24 per clip floor.
Discounts apply automatically in the cart and count boxes and cases toward the total.
RSIC-SI-1 ULTRA Specifications
- Width
- 3-5/8 in
- Height
- 9-1/6 in
- Depth
- 4-7/8 in
- Max spacing
- 24 in × 48 in on-center
- Max load
- 5 / 10 / 20 / 40 lb (spring color coded)
Hat channel specs
- Gauge
- 25 gauge (hemmed edge)
- Depth
- 7/8 in
- Width — top
- 1 1/4 in
- Width — bottom
- 2 1/2 in
RSIC-SI-1 ULTRA Project Calculator
Enter your surface square footage. We'll return a clip, channel, and screw count for your project — calculations run on our servers so estimates stay accurate as our field data improves.
Adds MLV over Good for a denser limp-mass layer.
Estimates follow PAC's ULTRA layout with 24" channel and 48" clip spacing.
STC Gauge
Compare how the RSIC-SI-1 ULTRA performs across assembly tiers. Select an assembly below to see the resulting STC score.
RSIC-SI-1 ULTRA + hat channel + double 5/8" drywall + Green Glue on insulated joists.
- STC 30-39: Loud speech clearly audible next room.
- STC 40-49: Loud speech muffled — normal residential wall.
- STC 50-59: Loud speech barely audible; suitable for offices & multi-family.
- STC 60+: Approaches studio-grade isolation.
How RSIC-SI-1 ULTRA compares
| Model | Primary Use | Isolation Element | Typical Layout | Notes |
|---|---|---|---|---|
| RSIC-SI-1 ULTRAthis | High-load wall/ceiling decoupling | Steel spring + elastomer | ≤24" channel · ≤48" clip o.c. | Best low-frequency control |
| RSIC-1 | General wall/ceiling decoupling | Elastomer | ≤24" · ≤48" | Popular all-around |
| RSIC-2 | Heavy ceilings | Elastomer (dual-deflection) | Project-specific | Dual-deflection design |
Applicable Assemblies
See where the RSIC-SI-1 ULTRA fits — from budget baseline to studio-grade isolation.
Best — RSIC-SI-1 ULTRA + Double Drywall + Green Glue + Insulation
Joists · Rockwool insulation · RSIC-SI-1 ULTRA + hat channel · 5/8" drywall · Green Glue · 5/8" drywall · acoustic sealant.
Better — RSIC-SI-1 ULTRA + Double Drywall + Green Glue
Joists · Rockwool insulation · RSIC-SI-1 ULTRA + hat channel · 5/8" drywall · Green Glue · 5/8" drywall.
Good — RSIC-SI-1 ULTRA + Silent FX Drywall
Joists · Rockwool insulation · RSIC-SI-1 ULTRA + hat channel · Silent FX damped drywall.
